Electric-furnace resistor



- Mar. I3, 1923.

o. A. coLBY' ELECTRIC FURNACE RESISTOR Filed June 5 WMM INVENTOR 0m' A a/by ATTORNEY Patented Mar. 13, 1923.

UNITED STATES ORA A. COLBY, F IRWIN. PENNSYLVAITIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ELECTRIC- FU RNACE RESISTOR.

Application led Junc 3,

To all 'whom it may concern:

Be it known that I, ORA A. Conor, a citizen of the United States. and a resident of Irwin,in the county of lVestmoreland and State of Pennsylvania, have invented a new and useful Improvement in Electric-Furnace Resistors, of which the following is a specilication.

My invention relates to electric furnaces l0 and particularly to electric-resistance furnaces and it has for its object to provide a relatively simple and inexpensive combina tion granular and solid resistor for such furnaces.

In co-pending application, Serial No. 454,776, filed March 23, 1921, Patent Number 1,443,580 byG. M. Little and assigned to the Westinghouse Electric & Manufacturing Company, there is disclosed an elec tric-resistance furnace in which the, resistor comprisesna.v pluralityof, relatively thin fiat carbonaceous plates, the flat surfaces being ressed-togel :l ie r` byuitable resilient means.

Ilhe resistance of such a resistoris relatively low and a relatively large current is required to produce the tempera-turc desired in the furnace chamber.

My present invention discloses a combined resistor comprising a plurality of dished carbonaoeous members in which granular-electric conducting material may be placed, the dished members being of such form as to permit of com ressing the granular material in the dis ed members and simultaneousl interlocking them.

In the sing e sheet of drawings:

Figure 1 is a View, in vertical cross-section, of an electric-resistance furnace comprising the device embodying my invention;

Fig. 2 is a view, in vertical cross-section, of a portion of the device embodying my invention, and

Fig. 3 is a view, in side elevation, of one of the dished members illustrated in Fig. 2.

An electric-resistance furnace ,10 comprises an outer metallic casing or framework 11 provided with suitable supporting members 12. Outer walls 13 comprise a plurality of bricks or blocks of heat insulating material located in the casing 11. Inner walls 14 comprise a plurality of bricks or blocks of any suitable high-tempcratnre-resistin0r material, the walls 14 being suitably spaced apart to form a furnace chamber l5 1921. serial No. 474,744,

of any suitable or desired contour and dimensions.

A heating element, located in the chamber l5, comprises a plurality of dished elements 16 to be described hereinafter more in detail. .1 graphite terminal block 17 is provided at one end of the built-up heating element the outer surface of which is operatively engaged by an elongated carbonaceous electrode 18 extending through the furnace walls 13 and 14.

The outer end of the electrode 18'has mounted thereon a metallic contact terminal Y19 to which the supply-circuit conductors (not shown) may be connected.

A resilient compressing-means for the built-up heating element comprises a suitably mounted adjusting screw 20,.engagi.ng the outer end of a helical spring 21the inner end of which engagesthe-outer surface of the contact terminal-19, an insulating member 22 being placed between fthe'Spring and the terminal to suitably insulate them from each other. It is to be understood that the compressing means illustrated inA Figure 1 is schematic only and that any suitab e or desired compressing means may be employed.

In order to suitably insulate the contact terminal 19 from the metallic framework 11, a member 23 of asbestos may be placed in the outer wall 13 and the casing 11, surrounding the contact terminal 19 to effectively in` sulate the terminal from the casing.

As the temperature of the electrode 18 is relatively very high at that part located at about the middle of the two walls 13 and 14, it is desirable that some means be provided to protect the electrode against oxidizing air enteringI from the outside and tendinv to How along the terminal 19. To this e'n I provide a well or hopper 24 in which is placed a mass 25 of granular carbonaceous material which may be tightl tamped in place around the electrode. his means is full described and claimed in a copending app ication, and its action is not, therefore, further described here.

Each of the members 16 is in the form of a relatively shallow plate, preferably of a carbonaceons material, having a depression 2G in one surface and a corresponflinv projection 27 in the other surface thereof he depression 2G provides a receptacle for a muss28 of ri-anular enrhonnrggnisA resistor materiell Whici is placed thereinV -ln order to build up the heating element it is only .necessary toplce u suituble number of inem4 5 bers'l onli. itizible'.*withv the glepressi-o11 2G facing upvardly, 'fill'the depressions with ranular carbonaceous material 2810 substantially the top surface of the plate. '."he members 16 may now. beplaced one :ihm-'e another, and, if slightl)r compressed: :i pm. 'j'ecfion 27maybecaused to interfit with :i depression 26, compressing the materia! thereinlaznd also causing the adjacent meinA bers16tolinterlockjvitli each other. The completed*heating-element muy now be placedinjts operative position .in the fnr- 'nacechamber -substzintiel 13'' as illustrated imF' re`1,.and compression may be em- 'ploy 4-tomnintainlthmhating element in -its operative :position therein.'

It may, be'noted thats the use of the device exbiilymgmyjnventlon provides n bnilt` up rsistor'- 'comprising solidend grnnnlnr a-ibnaeous'mtexzia'l, the lniilt up resistor h aving-a-relatifely high resistance. The 'device embodyng'myinvention provides nu interlocking-'resistor fwhich. :at the saine ",timfpro'vldes means for preventing i the idntion ofthelgranulnr materiel. -It may 30 bejhotedjl'furtheirf tht.' the resistor element '-.is -relgtivelyfsimple'xnolded ,member and .ftietithe beatingelemet'rnay be easily built Various modifications `may be made in the device embodyinglr my invention without depui-Ling from the spirit, und scope thereof und I desire that only such limitatiisshall be placed. thereon as. aire 'imposed by' the prior nrt or are 'specificallyl set forth in the appended claims.

l claim :is my invention:

1, In an electric furnace, the combination with a plurality of walls surronndindva. furimee chamber, of n resistor in said chamber comprising :i plurality of (lished refractory electric-nl-comlncting members, ranular-=re sister material in eachof sai dished refractory members and resilient meansjfor maintainingr said dished members inLinterlocked position in said furnace chamberifree of said walls.

:i plurality of relatiiely-shallow rfrac electrical-conducting members, each.- member hevinga-deplression in' onelsurface a'ndga corresponding' projection on the adjacent pnrellel surface, a quantity of. granulfelectrieal-resistor material inieacli of said idepressions, and means for maintainingthe projection of one member in operative l position in the depression of an adjacent"mem ber.

2. An electric furnace resistor compl-ling In testimony whereof, I have hereunto snbscribed my name this 26th' day offMay. 1921.

ORA A. 

